The invention relates to improvements in apparatus for intermittently advancing pallets or other objects. More particularly, the invention relates to improvements in apparatus of the type wherein the objects can be advanced by a rotor which has a circumferential helical groove for followers extending from the objects to be advanced.
Published German patent application No. 32 24 330 of Schollmayer discloses an apparatus wherein successive pallets of a series of pallets are caused to advance on a roller conveyor into the range of an intermittently driven cylindrical conveyor. The cylindrical conveyor is rotatable about an axis which is parallel to the direction of advancement of pallets and its peripheral surface has an open-ended helical groove for downwardly extending followers provided at the undersides of pallets which approach the rear end of the cylindrical conveyor by moving along the roller conveyor. The rollers of the roller conveyor are idler rollers. The rearwardly facing end face of the cylindrical conveyor constitutes a stop for the oncoming foremost pallet. The central section of the helical groove in the peripheral surface of the cylindrical conveyor extends in the circumferential direction of the conveyor, and a surface bounding a portion of the central section and facing counter to the direction of advancement of pallets constitutes a stop for a pallet which is already engaged by the cylindrical conveyor. Special drive means are necessary to set in motion a pallet which was arrested by the second stop. Alternatively, it is necessary to provide a complex synchronizing system which replaces the specially designed drive means. The relatively long cylindrical conveyor contributes to overall length of the apparatus. Moreover, the interval of time which is required to advance a pallet beyond the cylindrical conveyor is relatively long.
Other conventional pallet advancing apparatus are disclosed in French Pat. No. 2.071.993 granted to Giddings & Lewis, Inc. and in French Pat. No. 2.228.012 granted to Ossbahr.